WERC Highlights -- January 2007

Toxoplasmosis Infection and Cultural Traits: On Jan. 28, 2007, an article in The Capital (Annapolis, MD) about the role that the parasite Toxoplasma gondii may play in shaping culture cited a study by USGS scientist Kevin Lafferty: http://www.hometownannapolis.com/cgi-bin/read/2007/01_28-32/LIF. (Kevin Lafferty, Santa Barbara, CA, 805-893-8778, klafferty@usgs.gov)

Avian Influenza: On Jan. 31, 2007, USGS scientist John Takekawa discussed wild bird surveillance efforts to detect avian influenza with a freelance producer who plans to pitch a story on avian influenza to Dan Rather Presents, an HD satellite program. The story would likely focus on avian influenza surveillance efforts in California that involve testing migratory shorebirds and waterfowl, as well as international efforts to satellite track the migration of wild waterfowl that have been fitted with GPS devices. (John Takekawa, Vallejo, CA, 707-562-2000, john_takekawa@usgs.gov)

USGS to Participate at Desert Managers Meeting: The Desert Managers Group (DMG) will hold its winter meeting Jan. 31 – Feb. 1, 2007, in San Diego, Calif. USGS scientist and center director Steven Schwarzbach, USGS Western Ecological Research Center, will present the current status of its projects in the California deserts. The DMG was established as the forum for government agencies in the California deserts to address and discuss issues of common concern. For more: http://www.dmg.gov/index.php. (Steve Schwarzbach, Sacramento, CA, (916) 278-9490, steven_schwarzbach@usgs.gov)

USGS Scientist Invited to Join Forest Science Editorial Board: USGS scientist Jon Keeley of the Western Ecological Research Center has been appointed to the editorial board of the journal Forest Science, to serve a 3-year term as associate editor for wildland fire. A publication of the Society of American Foresters, Forest Science is internationally renowned as a leading forestry research journal. For more than 45 years, it has been publishing significant articles in forestry research: silviculture, soils, biometry, disease, recreation, photosynthesis, and tree physiology as well as all aspects of management and harvesting, and policy analysis. (Jon Keeley, Three Rivers, CA, 559-565-3170, jon_keeley@usgs.gov)

Studies Document a Changing Mojave Desert: USGS studies in a recent special volume of the Journal of Arid Environments shed light on a changing Mojave Desert and causes. USGS scientist Kristin Berry is guest co-editor of the special volume with Robert W. Murphy of the Royal Ontario Museum, and USGS scientists are authors of eight articles covering several topics such as precipitation, invasive plants, fire, contaminants, and the threatened desert tortoise. (Kristin Berry, Moreno Valley, CA, 951-697-5361, kristin_berry@usgs.gov)

Population Attributes of Desert Tortoises at the National Training Center, Fort Irwin, California: Located in the central Mojave Desert, the National Training Center at Fort Irwin contains habitat for the threatened desert tortoise, an indicator species of desert ecosystem health. While similar causes of death and cumulative disturbances of habitat occur elsewhere in the geographic range of the desert tortoise, military bases such as Ft. Irwin have a unique set of disturbances typical of training areas. A recent USGS study published in the Journal of Arid Environments provides a snapshot of Ft. Irwin tortoise population attributes, status, and relationships between tortoise densities and human activities. USGS scientist Kristin Berry and colleagues sampled 21 study plots at the National Training Center once between 1997 and 2003. Their survey revealed low densities and high death rates of desert tortoises on most plots. Tortoises had died from multiple anthropogenic causes, and many showed moderate to severe signs of disease. For more: http://www.werc.usgs.gov/pubbriefs/berrypbjan2007a.html. (Kristin Berry, Moreno Valley, CA, 951-697-5361, kristin_berry@usgs.gov) Citation: Berry, K. H., T. Y. Bailey, and K. M. Anderson. 2006. Attributes of desert tortoise populations at the National Training Center, Central Mojave Desert, California, USA. Journal of Arid Environments 67:165–191.

Abundance and Distribution of Selected Elements from Tortoise Habitats in the Mojave and Colorado Deserts: In a recent study in the Journal of Arid Environments, USGS scientists Maurice Chaffee and Kristin Berry conducted a baseline and background chemical survey in southeastern California to identify potential sources of toxicants in natural and human-altered habitats of the threatened desert tortoise. They collected soil, stream sediment, and plant samples from six tortoise study areas in the Mojave and Colorado deserts and analyzed them for up to 66 different elements. In addition to undisturbed lands, the six areas included some disturbed by mining activity, some subjected to military maneuvers, as well as some transected by paved roads or railroads. Of elements in soils that might have been toxic for tortoises, only arsenic appeared to be anomalous region-wide. The source of elevated levels of arsenic and mercury in ill desert tortoises from the western and central Mojave Desert may be from soils and plants near mines that contained anomalous concentrations of these elements. For more: http://www.werc.usgs.gov/pubbriefs/berrypbjan2007b.html. (Maurice Chaffee, Denver, CO, 303-236-1855, mchaffee@usgs.gov; Kristin Berry, Moreno Valley, CA, 951-697-5361, kristin_berry@usgs.gov) Citation: Chaffee, M. A., and K. H. Berry. 2006. Abundance and distribution of selected elements in soils, stream sediments, and selected forage plants from desert tortoise habitats in the Mojave and Colorado deserts, USA. Journal of Arid Environments 67:35–87.

Spatial and Temporal Patterns of Wildfires in the Mojave Desert: Fire has been historically infrequent in the Mojave Desert, and its increased prevalence caused by the invasion of non-native annual grasses is a major concern for land managers there. Using fire data from the U.S. Department of the Interior and Forest Service interagency fire record database for 1980–2004, USGS scientists Matt Brooks and J. R. Matchett found that the most dramatic changes during this 25-year period have occurred in middle elevation shrublands dominated by creosotebush, Joshua tree, and/or blackbrush, where most of the fires occurred. Results from their study suggest that an invasive plant/fire regime cycle is currently establishing in the middle and possibly the low elevation shrublands of the Mojave Desert, but not at higher elevations. The study is published in a recent issue of the Journal of Arid Environments. For more: http://www.werc.usgs.gov/pubbriefs/brookspbjan2007c.html. (Matt Brooks, Henderson, NV, 702-564-4615, matt_brooks@usgs.gov) Citation: Brooks, M. L., and J. R. Matchett. 2006. Spatial and temporal patterns of wildfires in the Mojave Desert, 1980–2004. Journal of Arid Environments 67:148–164.

Effects of Livestock Watering Sites on Alien and Native Plants in the Mojave Desert: Artificial watering sites can have significant ecological effects in arid and semi-arid desert ecosystems where standing surface water is uncommon. One major effect is the grazing and activity patterns of large herbivores that converge around artificial watering sites. This activity results in a disturbance gradient called a “piosphere.” USGS scientists Matt Brooks, Kristin Berry, and J. R. Matchett studied responses of alien and native annual plants and native perennial plants within 9 piospheres in the Pilot Knob grazing allotment in the west-central Mojave Desert, California. They found that absolute and proportional cover of alien annual plants increased with proximity to watering sites, whereas cover and species richness of native annual plants decreased. Significant effects focused within 200 m of the watering sites, suggesting that control efforts for alien annual plants and restoration efforts for native plants should optimally be directed at the central part of the piosphere gradient. Their study is published in a recent issue of the Journal of Arid Environments. For more: http://www.werc.usgs.gov/pubbriefs/brookspbjan2007b.html. (Matt Brooks, Henderson, NV, 702-564-4615, matt_brooks@usgs.gov) Citation: Brooks, M. L., J. R. Matchett, and K. H. Berry. 2006. Effects of livestock watering sites on alien and native plants in the Mojave Desert, USA. Journal of Arid Environments 67:125–147.

Dominance and Environmental Correlates of Alien Annual Plants in the Mojave Desert: Land managers are concerned about the negative effects of alien annual plants on native plants, threatened and endangered species such as the desert tortoise, and ecosystem integrity in the Mojave Desert. Results from a recent study in the Journal of Arid Environments by USGS scientists Matt Brooks and Kristin Berry can be used in estimating the baseline dominance of alien annual plants across the region. They documented the biomass dominance of alien annual plants and their environmental correlates during two years of contrasting rainfall in three Desert Wildlife Management Areas and critical habitat for the federally threatened desert tortoise, representing the central, southern, and western Mojave Desert. Their findings indicate that alien plant species comprised a small fraction of the total annual plant flora, but most of the annual plant community biomass. The results of this and other studies suggest that the proportion of biomass from alien species in the annual plant community may seldom drop below 50% during years of above-average rainfall, and is typically much higher during years of low rainfall. For more: http://www.werc.usgs.gov/pubbriefs/brookspbjan2007a.html. (Matt Brooks, Henderson, NV, 702-564-4615, matt_brooks@usgs.gov) Citation: Brooks, M. L., and K. H. Berry. 2006. Dominance and environmental correlates of alien annual plants in the Mojave Desert, USA. Journal of Arid Environments 67:100–124.

Toxoplasmosis Infection and Cultural Traits: An article in the February 2007 issue of Discover magazine mentions a study by USGS scientist Kevin Lafferty that suggested a behavioral manipulation by a common brain parasite, Toxoplasma gondii, may play a role in cultural change. (Kevin Lafferty, Santa Barbara, CA, 805-893-8778, klafferty@usgs.gov)

Sea Otter Research: California sea otter research will be featured at 7:30 PST on Tues., Feb. 6, 2007, in Sea Otters Mystery, during the debut of “Quest,” a new science, nature and education series on KQED-TV (public television, San Francisco). Sea otter scientists from the USGS, University of California at Santa Cruz, California Department of Fish and Game, and Monterey Bay Aquarium were interviewed and filmed for the sea otter story. For more on viewing schedule: http://www.kqed.org. (Brian Hatfield, San Simeon, CA, 805-927-3893, brian_hatfield@usgs.gov)

Mountain Yellow-legged Frogs: On Jan. 8, 2006, USGS scientist Adam Backlin of the Western Ecological Research Center was contacted by the San Diego Union-Tribune and San Bernardino Sun regarding the mountain yellow-legged frog in southern California. The reporters were gathering information for future stories about a group of rescued tadpoles that are being nurtured in captivity in a collaborative effort to help restore this endangered frog. (Adam Backlin, Irvine, CA, 714-508-4702, abacklin@usgs.gov)

Night Light Pollution: USGS scientist Robert Fisher of the Western Ecological Research Center was interviewed about ecological effects of artificial night lighting on wildlife in southern California in the January/February issue of Zoogoer, the magazine of Friends of the National Zoo: http://nationalzoo.si.edu/Publications/ZooGoer/2007/1/light.cfm. (Robert Fisher, San Diego, CA, 619-225-6422, rfisher@usgs.gov)